Image stacking to keep objects

[RockyMM]

Hey guys,

 

I am hobbyist user, so it's not a great deal if you cannot help me.

 

I am trying to stack several photos, but to have the opposite of "object removal using stacks". I have four photos taken from the same point with my two friends sitting at the table and exchanging position between each shot. What I want to achieve is to have each of them several times in the final image. If I use Median stacking, then almost everything disappears from the photo with only table remaining and some ghosting. So I need to use masking, but that's where it gets a bit complicated. I tried Outlier stacking but that produces some artefacts and needs a bit refining, for which I also need some masking.

 

For the stack I have live stacking checked.

 

So I guess the question is how to most efficiently create masks from and for each stack layer? I figured I would select part of the one friend on one photo, e.g. hand, head and part of the body, and then I would apply the resulting mask to all other photos in the stack. But I would need to add all masks for all body parts to all photos... So that makes it a bit daunting. Not helping is that when I Alt-click on a layer and start selecting using Flood select tool that the selection outline is shifted several pixels to the left in comparison to photo itself. Also, I cannot get the tolerance to right amount; it always selects something from the background or not enough of what I need.

 

Also, which blending mode would suit me the most?

 

Do you have some other suggestion how to achieve what I want?

 

Thanks!

 

P.S. I've found that if I stack only two photos and then use Standard deviation as the stack operator that produces black areas where the photos are the same and some type of blending in the areas where there are differences. That seems like a good starting point for a mask. How to create a mask from such stack result?

Edited January 14, 2018 by RockyMM

[John Rostron]

It would help if we could see these images (preferably smallish jpegs, say 640px). 

The approach I would use is to stack the images with the nearest subjects at the top and the blend mode set to Normal. Then, set the opacity of the top layer to 50% and erase the areas just showing the friends you want to appear from the next layer down. I cannot be too specific without seeing your images.

John

[DWright]

Hi RockyMM,

 

Welcome to the forum

 

To do this I would not use the stack option in Affinity Photo rather I would open all 4 photos and on the second to forth photos i would do the following

 

1. Select the objects using the selection brush refining the selection as needed

 

2. Invert the selection and press delete to remove the other objects in the photo

 

3. Invert the selection again and from the Edit menu choose Copy

 

4. Goto the first photo and from the Edit menu choose Paste to insert the cutout objects as a new layer

 

5. repeat the steps for the remaining images

 

The advantage of this is that you can adjust each addition layers to the best positions on the original photo

[John Rostron]

This is an intreaguing approach. I have a related problem. I took six hand-held photos of the Thames estuary at Southend with the sun setting. I wish to align these images so I can display them in sequence with the background remaining fixed. If I use the Load files into Stack method and tick Align, then it will attempt to align to the sun. I therefore left Align unticked and aligned by hand, using a couple of buoys as markers.

This worked, but I will have another go using a version of @DWright's techniques.

John

[RockyMM]

Hey guys!

 

Thank you for the replies. The reason why I used stacks in the first place is that aligns the photos perfectly since the photos were taken from hand, not on the tripod.

 

 

Here are the photos in question in the attachment.

 

It's not easy to cut the subjects since there is hair involved and possibly some overlap with the background. Another thing, we were not thinking about compositing too much when we took these photos, so it happens that the same photo has the subject that needs to go in the front and another that needs to go to the back.

 

[carl123]

A quick cut and paste test suggests it's probably not worth the effort doing this properly with these images.

The lady in particular is virtually covered in 2 places on the final composition and the only full shot of her just shows her back.  There is nothing there to convincingly suggest it is the same lady in 3 different positions.

A really nice idea for a picture but it needs thinking about before taking the individual shots.  (not easy)

Oh, and get a tripod, the background needs to be the same (pixel aligned) in all images, minor fluctuations will make the final alignment much harder

[firstdefence]

These images take more thinking than you realise, they can look great when done well and add a splash of comedy into the mix, also recolouring such as the red coat would be fairly easy too. Might have a doodle to see what I can come up with lol

[firstdefence]

I've used a few techniques in this image, including selection and erase, New Panorama - yes I know odd but it worked for some of the image composition and a bit of replace colour to define the girl with the back to the camera.

merged images.afphoto

[carl123]

Using just 4 people is probably a better composition for these images

 

[firstdefence]

2 hours ago, carl123 said:

Using just 4 people is probably a better composition for these images

 

Yes I considered that too but for the sake completeness I used all the people. These sort of photographs do take a bit of forethought with regard to backgrounds and composition.

[RockyMM]

Wow, such a good effort from you guys. Thank you so much!

 

I will try the attached afphoto project file. 

 

I was thinking that I could forgo the copy of the girl when she is closest to the camera and use remaining ones. Seeing this in photos you guys created helped me realize that. I mean, I knew it would not look good, but only now I am certain that having her in the foreground with her back turned is not a good idea. 

 

13 hours ago, firstdefence said:

These images take more thinking than you realise, they can look great when done well and add a splash of comedy into the mix, also recolouring such as the red coat would be fairly easy too. 

 

Exactly. Next time we would put some thinking into this  

[firstdefence]

How about a few ideas people...

• You could have your clones stood nearby like two strangers having a conversation or argument and another clone walking into a lampost or glass door. 
• Clones standing in a queue at a bus stop all doing funny stuff.
• Clones going up and down an escalator.